Varactor-tuned dual-mode bandpass filter for wireless applications

Author

Djoumessi, E.E. ; Chaker, M. ; Wu, Ke

Author_Institution

Dept. of Electr. Eng., Ecole Polytech., Montreal, QC

fYear

2009

fDate

18-22 Jan. 2009

Firstpage

646

Lastpage

649

Abstract

A tunable dual-mode microstrip bandpass filter for mobile GSM and ISM bands (2000 MHz to 2.45 GHz) is proposed and characterized. The structure is composed of a meander loop dual-mode resonator and four loading capacitances. Perturbation of the degenerate modes is achieved by combination of a small square patch and an additional meander line resonator. Frequency tuning is made possible by modifying the electrical length of orthogonal quarter-wavelength meander arms with four varactor-diode capacitors. The measured insertion loss of a filter prototype realized on alumina substrate is between 3.5 dB to 7 dB over the tuning frequency range, with a constant 3-dB bandwidth of about 5.75%. The filter exhibits a center-frequency tunability of 20%.

Keywords

UHF filters; band-pass filters; cellular radio; circuit tuning; resonators; varactors; ISM bands; alumina substrate; frequency 2000 MHz to 2.45 GHz; frequency tuning; insertion loss measurement; meander line resonator; meander loop dual-mode resonator; mobile GSM band; perturbation modes; square patch resonator; varactor-diode capacitors; varactor-tuned dual-mode bandpass filter; wireless applications; Arm; Band pass filters; Capacitance; Capacitors; Frequency measurement; GSM; Loss measurement; Microstrip filters; Resonant frequency; Tuning; Tunability; alumina; dual-mode; filter; varactor diode; wireless bands;

fLanguage

English

Publisher

ieee

Conference_Titel

Radio and Wireless Symposium, 2009. RWS '09. IEEE

Conference_Location

San Diego, CA

Print_ISBN

978-1-4244-2698-0

Electronic_ISBN

978-1-4244-2699-7

Type

conf

DOI

10.1109/RWS.2009.4957434

Filename

4957434